Practical ideas.

Idea twitchs tooth form from sketch

Sometimes it takes a drawing to duplicate a gear. My idea is an easy way of drawing a gear-tooth form. The example shown is a 30-tooth, 5-diametral pitch, 6-in.-pitch diameter, 314 chordal thickness, and a 145 [degrees] compressing angle.

I establish the odyllic force pitch diameter, and root diameter from the gear centerline and lay without the chordal thickness as shown I then establish the crushing angle at the root diameter using a protractor or by means of finding the sine of 145 [degrees] and lay them without as indicated in the drawing. I mark the radius at